Did you hear the big news from Wednesday? No, I’m not talking about the continuing firestorm over President Trump’s firing of FBI Director James Comey. I mean the Senate’s stunning defeat of a measure that would have rolled back clean air protections—though, as we’ll see, the two are oddly connected.

Here’s what happened: 

On Wednesday, the Senate voted 51 to 49 against a resolution that would have overturned an Obama administration rule tightening restrictions on methane emissions on public lands. The vote was a shocker. Senate majority leader Mitch McConnell, the Kentucky Republican, rarely ever schedules a vote without knowing he’ll prevail. This time, his well-laid plans were frustrated. Democratic unity and the defection of Republicans Susan Collins of Maine, Lindsey Graham of South Carolina, and, in a last-minute surprise, Arizonan John McCain sunk the measure. 

Here’s why it’s important:

First, there will be a real environmental benefit from this vote. At least a fifth of U.S. oil and gas production occurs on public lands, and the Obama-era rule would prevent the release of about 180,000 tons of methane on Bureau of Land Management properties. Methane is at least 50 times more heat-trapping than carbon dioxide, so the Senate’s vote will help keep some global warming pollutants out of the atmosphere.  

Second, this is the most substantive legislative setback to President Trump’s anti-environment agenda since he took office. It’s no exaggeration to say that Trump’s most meaningful “accomplishment” in his first 100 days has been his reversal of Obama’s environmental record. (Just check out this discouraging National Geographic tracker of how Trump is “changing the environment.”) The GOP attempted to reverse the methane rule under an arcane procedure called the Congressional Review Act; among the first CRA resolutions passed by this Congress was an abolishment of the Stream Protection Rule, which would have prevented the dumping of mine waste in waterways. Wednesday’s vote marked the first time since Trump took office that Congress has not approved a CRA backed by the president. 

Third, the Senate showdown may provide a blueprint of sorts for how to orchestrate a legislative resistance to Trump’s dangerous agenda and threats to the rule of law. To keep the worst Trump-Pence-Ryan policies at bay, progressives have to find a way to run down the legislative clock on various measures and then use the chaos generated by Trump’s own whirlwind to land a fatal blow.

A funny thing about the CRA is that it can only be used within the first 60 legislative days of a new congressional session, and it can only address rules established in the final six months of the previous administration. (I did say it’s arcane. Did I also mention that it had only been used on one other occasion before Trump was elected?) May 10 was the final day that the vote on the proposed methane-rule reversal could happen. This was a do-or-die moment. 

The issue went to the last possible minute thanks to many Americans’ concern about the impacts of the latest oil and gas boom. For months, Republican senators including Dean Heller of Nevada, Cory Gardner of Colorado, and Rob Portman of Ohio were on the fence. Their hesitancy was an echo of their constituents’ concerns. Colorado is a major oil and gas state, Ohio has become a significant gas producer as well, and though Nevada is a minor player in the oil and gas industry, there’s a lot of federal land there and a lot of local opinions on how it should be managed.

“We know from public polling we did that most Coloradans support reasonable restrictions on fracking to protect the health and safety of individuals, families, and communities,” Jim Alexee, director of the Sierra Club’s Colorado Chapter, told me a few hours after the vote. “Coloradans support methane rules.” 

Gardner was an undecided vote until as late as Tuesday morning, according to Politico’s Morning Energy newsletter. Senator Portman didn’t commit to voting for the resolution until Monday, when Interior Secretary Ryan Zinke gave Portman assurances that the Interior Department would still find a way to address methane emissions. So Senator McConnell had strong confidence that the measure would pass—until McCain cast his surprise vote.

In a statement that echoed the very Tory, old-fashioned conservatism concerns of his pals Collins and Graham, the Arizona senator stated that when it comes to law-making, the CRA is too blunt of a tool.           

“I join the call for strong action to reduce pollution from venting, flaring, and leaks associated with oil and gas production operations on public and Indian land,” McCain’s statement said. “While I am concerned that the BLM rule may be onerous, passage of the resolution would have prevented the federal government, under any administration, from issuing a rule that is ‘similar,’ according to the plain reading of the Congressional Review Act.”      

That seems wise and judicious. But some political commentators say it seems more likely that McCain was motivated by his fury over the whole Russian election meddling–Michael Flynn–FBI director mess. 

Here’s a choice bit from The Intercept’s David Dyen’s vote postmortem about what might have motivated McCain to buck his party’s leadership: 

McCain’s conduct during the Senate vote also raises red flags. In the C-SPAN video of the vote, McCain can be seen in heated discussion with John Cornyn, R-Texas, the number two man in the Senate leadership, along with John Barrasso, R-Wyo., and an unidentified senator with his back to the camera. After yelling at them for close to a minute, McCain goes over to the Senate clerks and gives a thumbs down to record his vote. He then storms out of the chamber, as Cornyn raises his arms in mild protest.

McCain has a reputation for being a little, shall we say, vindictive. It’s not out of the question at all that he would torpedo this vote, regardless of his ideological preferences, because of a fit of pique about the FBI director he admires getting unceremoniously dumped. 

(Watch the C-Span clip and judge for yourself.)  

If this is, in fact, what happened, it offers a playbook for progressives trying to influence happenings on Capitol Hill. First, delay delay delay. While minority leaders Charles Schumer and Nancy Pelosi throw sand in the parliamentary gears, the grassroots have to stay busy making Trump’s retrograde agenda politically radioactive—just like with the rules around methane emissions. Then delay some more. And hope that by the time a big issue comes around a vote, Trump will have done something stupid enough to cost him the support he needs in Congress.  

Trump is, reliably, his own worst enemy. In a way, environmentalists and other progressives just have to manage to be his second-worst enemy.